铁路光传送网络是高速铁路地面基础设施的神经中枢,为避免网络故障给铁路运营带来巨大损失,重点研究光传送网P-Cycle(Pre-configured Cycle)保护技术,提出在圈扩展时以所有候选圈上未保护工作容量的方差、冗余度两个指标为比较标准的RVP...铁路光传送网络是高速铁路地面基础设施的神经中枢,为避免网络故障给铁路运营带来巨大损失,重点研究光传送网P-Cycle(Pre-configured Cycle)保护技术,提出在圈扩展时以所有候选圈上未保护工作容量的方差、冗余度两个指标为比较标准的RVPA(Redundancy and Variance Based P-Cycle Construction Algorithm)算法。圈扩展的过程中,算法将选择方差与冗余度能同时满足条件的候选圈作为本轮扩展圈,有效限制了完成保护的P-Cycle圈个数;圈扩展停止条件中,当UPL与参数M、冗余度的大小关系满足条件时,则停止圈扩展,从而限制圈上节点数,使圈个数与圈长度得到有效均衡;在仿真过程中,利用泛欧网络拓扑COST239对RVPA算法进行仿真,并对比分析不同M值下的性能。仿真结果表明,在相同空闲资源与待保护工作容量设定下,参数M取0.5时效果最优,并且RVPA算法的保护容量效率、所需圈的个数、算法整体耗时、总冗余度均优于已有的POCA(P-Cycle Optimization Configuration Heuristic Algorithm)算法。展开更多
In order to solve the bottleneck problem of the traditional K-Medoids clustering algorithm facing to deal with massive data information at the time of memory capacity and processing speed of CPU, the paper proposed a ...In order to solve the bottleneck problem of the traditional K-Medoids clustering algorithm facing to deal with massive data information at the time of memory capacity and processing speed of CPU, the paper proposed a parallel algorithm MapReduce programming model based on the research of K-Medoids algorithm. This algorithm increase the computation granularity and reduces the communication cost ratio based on the MapReduce model. The experimental results show that the improved parallel algorithm compared with other algorithms, speedup and operation efficiency is greatly enhanced.展开更多
目的探讨乳酸林格氏液和羟乙基淀粉130/0.4容量负荷治疗的效果。方法本研究为双盲前瞻性研究。选择2011年7月—2013年3月择期胃肠外科肿瘤手术患者81例,美国麻醉医生分级Ⅰ~Ⅱ,分成2组:Ⅰ组(羟乙基淀粉130/0.4容量负荷组,n=56)和Ⅱ组(...目的探讨乳酸林格氏液和羟乙基淀粉130/0.4容量负荷治疗的效果。方法本研究为双盲前瞻性研究。选择2011年7月—2013年3月择期胃肠外科肿瘤手术患者81例,美国麻醉医生分级Ⅰ~Ⅱ,分成2组:Ⅰ组(羟乙基淀粉130/0.4容量负荷组,n=56)和Ⅱ组(乳酸林格氏液容量负荷组,n=25)。麻醉诱导后予以3次容量负荷,每次3 m L·kg?1羟乙基淀粉130/0.4或者乳酸林格氏液,7 min输毕。麻醉前后、每次容量负荷后稳定5 min,记录平均动脉压(MAP)、每博心脏输出量指数(SVI)、血容量扩张效率和氧供(DO_2)。结果麻醉诱导期间SVI和MAP均降低,两组相当;Ⅰ组和Ⅱ组患者对3次容量负荷的反应性分别为64%对20%(P<0.001)、43%对13%(P<0.001)和23%对14%(P=0.101);而第1或2次容量负荷后Ⅰ组患者达到容量最优化的累计比例低于Ⅱ组(25%对74%,P<0.001;46%对81%,P<0.001),第3次2组差异无统计学意义(88%对89%,P=0.825)。3次容量负荷后SVI上升的幅度Ⅰ组(基础值86%)高于II组(基础值68%)(P<0.001),而MAP变化2组差异无统计学意义。第1次负荷后2种液体的血容量扩张效率相当,第2次和第3次负荷Ⅰ组高于Ⅱ组。麻醉诱导和血液稀释均导致氧供下降,2种液体之间没有区别。结论容量优化治疗中胶体液的容量治疗效果优于晶体液,建议采用胶体液进行容量负荷治疗。展开更多
Insulating ceramics are applied to modern manufacturing industries for their improved material properties.But they are the difficult-to-machine materials because of their high rigidity,high brittleness and non-electri...Insulating ceramics are applied to modern manufacturing industries for their improved material properties.But they are the difficult-to-machine materials because of their high rigidity,high brittleness and non-electrical conductivity.A new method which employs a high energy capacitor for electric discharge machining of insulating ceramics efficiently is presented in this paper,and the single discharge experiments have been carried out.The process uses the high voltage,large capacitor and high discharge energy,it is able to effectively machine insulating ceramics,and the single discharge crater volume of insulating ceramics can reach 17.63 mm3.The effects of polarity,peak voltage,capacitance,current-limiting resistance,tool electrode feed,tool electrode section area and assisting electrode thickness on the process performance such as the single discharge crater volume,the tool wear ratio and the assisting electrode wear ratio have been investigated.The microstructure of the discharge crater is examined with a scanning electron microscope(SEM).The results show that the discharge craters have sputtering appearance,the insulating ceramic materials are mostly removed by spalling,in the center region of the discharge some materials are removed by melting and vaporization,and the material removal is enhanced with the machining parameters increasing.展开更多
Biochar added to soil can improve crop growth through both direct and indirect effects, particularly in acidic, highly weathered soils in subtropical and tropical regions. However, the mechanisms of biochar improving ...Biochar added to soil can improve crop growth through both direct and indirect effects, particularly in acidic, highly weathered soils in subtropical and tropical regions. However, the mechanisms of biochar improving crop growth are not well understood. The objectives of this study were i) to determine the crop responses to biochar addition and ii) to understand the effect of biochar addition on N use efficiency. Seven acidic red soils varying in texture, p H, and soil nutrient were taken from southern China and subjected to four treatments: zero biochar and fertilizer as a control(CK), 10 g kg-1biochar(BC), NPK fertilizers(NPK), and 10 g kg-1biochar plus NPK fertilizers(BC+NPK).15N-labeled fertilizer was used as a tracer to assess N use efficiency. After a 46-d pot experiment,biochar addition increased soil p H and available P, and decreased soil exchangable Al3+, but did not impact soil availabe N and cation exchange capacity(P > 0.05). The N use efficiency and N retained in the soil were not significantly affected by biochar application except for the soil with the lowest available P(3.81 mg kg-1) and highest exchanageable Al3+(4.54 cmol kg-1). Greater maize biomass was observed in all soils amended with biochar compared to soils without biochar(BC vs. CK, BC+NPK vs. NPK). This agronomic effect was negatively related to the concentration of soil exchangeable Al3+(P < 0.1). The results of this study implied that the liming effect of biochar improved plant growth through alleviating Al toxicity and P deficiency, especially in poor acidic red soils.展开更多
文摘铁路光传送网络是高速铁路地面基础设施的神经中枢,为避免网络故障给铁路运营带来巨大损失,重点研究光传送网P-Cycle(Pre-configured Cycle)保护技术,提出在圈扩展时以所有候选圈上未保护工作容量的方差、冗余度两个指标为比较标准的RVPA(Redundancy and Variance Based P-Cycle Construction Algorithm)算法。圈扩展的过程中,算法将选择方差与冗余度能同时满足条件的候选圈作为本轮扩展圈,有效限制了完成保护的P-Cycle圈个数;圈扩展停止条件中,当UPL与参数M、冗余度的大小关系满足条件时,则停止圈扩展,从而限制圈上节点数,使圈个数与圈长度得到有效均衡;在仿真过程中,利用泛欧网络拓扑COST239对RVPA算法进行仿真,并对比分析不同M值下的性能。仿真结果表明,在相同空闲资源与待保护工作容量设定下,参数M取0.5时效果最优,并且RVPA算法的保护容量效率、所需圈的个数、算法整体耗时、总冗余度均优于已有的POCA(P-Cycle Optimization Configuration Heuristic Algorithm)算法。
文摘In order to solve the bottleneck problem of the traditional K-Medoids clustering algorithm facing to deal with massive data information at the time of memory capacity and processing speed of CPU, the paper proposed a parallel algorithm MapReduce programming model based on the research of K-Medoids algorithm. This algorithm increase the computation granularity and reduces the communication cost ratio based on the MapReduce model. The experimental results show that the improved parallel algorithm compared with other algorithms, speedup and operation efficiency is greatly enhanced.
文摘目的探讨乳酸林格氏液和羟乙基淀粉130/0.4容量负荷治疗的效果。方法本研究为双盲前瞻性研究。选择2011年7月—2013年3月择期胃肠外科肿瘤手术患者81例,美国麻醉医生分级Ⅰ~Ⅱ,分成2组:Ⅰ组(羟乙基淀粉130/0.4容量负荷组,n=56)和Ⅱ组(乳酸林格氏液容量负荷组,n=25)。麻醉诱导后予以3次容量负荷,每次3 m L·kg?1羟乙基淀粉130/0.4或者乳酸林格氏液,7 min输毕。麻醉前后、每次容量负荷后稳定5 min,记录平均动脉压(MAP)、每博心脏输出量指数(SVI)、血容量扩张效率和氧供(DO_2)。结果麻醉诱导期间SVI和MAP均降低,两组相当;Ⅰ组和Ⅱ组患者对3次容量负荷的反应性分别为64%对20%(P<0.001)、43%对13%(P<0.001)和23%对14%(P=0.101);而第1或2次容量负荷后Ⅰ组患者达到容量最优化的累计比例低于Ⅱ组(25%对74%,P<0.001;46%对81%,P<0.001),第3次2组差异无统计学意义(88%对89%,P=0.825)。3次容量负荷后SVI上升的幅度Ⅰ组(基础值86%)高于II组(基础值68%)(P<0.001),而MAP变化2组差异无统计学意义。第1次负荷后2种液体的血容量扩张效率相当,第2次和第3次负荷Ⅰ组高于Ⅱ组。麻醉诱导和血液稀释均导致氧供下降,2种液体之间没有区别。结论容量优化治疗中胶体液的容量治疗效果优于晶体液,建议采用胶体液进行容量负荷治疗。
基金supported by the National Natural Science Foundation of China (Grant No 50675225)the Ministry of Science and Technology of China (Grant No 2009GJC60047)
文摘Insulating ceramics are applied to modern manufacturing industries for their improved material properties.But they are the difficult-to-machine materials because of their high rigidity,high brittleness and non-electrical conductivity.A new method which employs a high energy capacitor for electric discharge machining of insulating ceramics efficiently is presented in this paper,and the single discharge experiments have been carried out.The process uses the high voltage,large capacitor and high discharge energy,it is able to effectively machine insulating ceramics,and the single discharge crater volume of insulating ceramics can reach 17.63 mm3.The effects of polarity,peak voltage,capacitance,current-limiting resistance,tool electrode feed,tool electrode section area and assisting electrode thickness on the process performance such as the single discharge crater volume,the tool wear ratio and the assisting electrode wear ratio have been investigated.The microstructure of the discharge crater is examined with a scanning electron microscope(SEM).The results show that the discharge craters have sputtering appearance,the insulating ceramic materials are mostly removed by spalling,in the center region of the discharge some materials are removed by melting and vaporization,and the material removal is enhanced with the machining parameters increasing.
基金Supported by the National Key Technology R&D Program of China(No.2011BAD31B04)the National Natural Science Foundation of China(Nos.41371235 and 41171191)
文摘Biochar added to soil can improve crop growth through both direct and indirect effects, particularly in acidic, highly weathered soils in subtropical and tropical regions. However, the mechanisms of biochar improving crop growth are not well understood. The objectives of this study were i) to determine the crop responses to biochar addition and ii) to understand the effect of biochar addition on N use efficiency. Seven acidic red soils varying in texture, p H, and soil nutrient were taken from southern China and subjected to four treatments: zero biochar and fertilizer as a control(CK), 10 g kg-1biochar(BC), NPK fertilizers(NPK), and 10 g kg-1biochar plus NPK fertilizers(BC+NPK).15N-labeled fertilizer was used as a tracer to assess N use efficiency. After a 46-d pot experiment,biochar addition increased soil p H and available P, and decreased soil exchangable Al3+, but did not impact soil availabe N and cation exchange capacity(P > 0.05). The N use efficiency and N retained in the soil were not significantly affected by biochar application except for the soil with the lowest available P(3.81 mg kg-1) and highest exchanageable Al3+(4.54 cmol kg-1). Greater maize biomass was observed in all soils amended with biochar compared to soils without biochar(BC vs. CK, BC+NPK vs. NPK). This agronomic effect was negatively related to the concentration of soil exchangeable Al3+(P < 0.1). The results of this study implied that the liming effect of biochar improved plant growth through alleviating Al toxicity and P deficiency, especially in poor acidic red soils.
